An out gay Conservative who is a close friend of David and Sarah Cameron has revealed that the party leader’s wife persuaded her husband to support the abolition of Section 28.

Speaking to The Guardian Nick Boles, founder of the Policy Exchange thinktank, said that David Cameron’s change of heart on gay issues was in part due to Sarah.

Referring to Mr Cameron’s previous support for Section 28, Mr Boles said:

“I think she had a much stronger sense of how unacceptable that piece of legislation was … and she helped him understand it. She always got why it was so offensive.”

Mr Boles was a strongly-tipped candidate for the Tory nomination for Mayor of London, but withdrew in July when he was diagnosed with Hodgkins Lymphoma, a type of cancer.

The party’s nomination was won by fellow Cameron ally Boris Johnson yesterday.

An influential member of the “Notting Hill set,” Mr Boles was a parliamentary candidate in the 2005 election. He came within 500 votes of winning Hove.

Earlier this year he was ranked 27 in the Independent on Sunday Pink List of the most influential gay people in the UK.

He is expected to make a full recovery and return to frontline politics.

The Guardian profile of Mrs Cameron also revealed that she previously voted Green and may have had some influence on his thinking in this area.

Mrs Cameron, 36, is a director of upmarket stationers Smythson of Bond Street.

She will be in the public eye in the coming week as she attends the Conservative party conference in Blackpool with her husband.